Nearly two weeks later, we find out that Facebook dropped another half-billion dollars on a patent buy from Microsoft – who had purchased that chunk of patents and more from AOL for a billion bucks around the same time Facebook bought Instagram.

Courtesy LinkedIn

That might qualify as a spending spree. And when one social media giant whips out its checkbook like that, you can bet a handful of other players start to wriggle a bit in their office chairs. On the other side of things, when one of those checks gets delivered to the owners of an app, you can bet the sea of app developers starts to roil and swell with the “next big thing” hoping to emerge from the churn and become overnight gazillionaires.

There’s already talk of the next big acquisition – both from a financial and strategic perspective.

Now the showdown begins. Who buys BranchOut? It directly competes with LinkedIn, and some have started to prod the leading professional social network to buy the damn thing before Facebook whips out the checkbook again. It would seem to make sense for LinkedIn to make a move for a company like BranchOut. The app seems poised to have a ton of reach into areas where LinkedIn might be lacking, regardless of LinkedIn’s 150 million-strong user base – younger, less affluent folks looking to use what may be more authentic social media connections (friends, family, etc.) to find a job. LinkedIn has more of a buttoned-up, handshake-and-business card feel to it.

Regardless of the gains to be made – substantive, face-saving or otherwise – the race to find the next big app raises concern.

Has the sting of the Dot Com bubble bursting faded enough for the industry to shuffle right into the App Bubble (there’s got to be a better name for that – Abble? Maybe not)? Maybe shuffle isn’t the right word. Maybe it’s more like “careen headfirst into with abandon.” I’m sure Instagram is a wonderful app and no offense meant to any die-hard users (I have the app, but don’t use it often), but is it $1 billion of awesome? (Don’t forget the initial asking price was twice that.)

It would be hard to argue that not buying Instagram would have significantly impeded Facebook’s juggernaut growth spiral towards a billion registered users. On the other hand, you could make a case that LinkedIn is under direct threat from an app like BranchOut – a similar service that is tied into Facebook’s mammoth user base. Imagine the price-tag on that one.

This sale – or bidding war or whatever it turns out to be – might just let us know how big the App Bubble could get. This is where a market inflated by Facebook’s fat stacks of money (soon to be post-IPO fatter) meets LinkedIn’s actual competitive need for acquisition. Both, of course, are competing for the almighty ad dollar, albeit in two seemingly different ways – Facebook lures advertisers with the sheer size of its network and LinkedIn touts unmatched targeting power of affluent demographics.

I hope LinkedIn either has deep pockets or the sense to make a smart buy – and not a scared one.